5^4 



NATURE 



[October io, 1S95 



requirements for the i>ro\nsion for safety in marine l)oiIers and 

 enginees. The want of uniformity here again is undoubte<l. 



Lieut. B. Baden-Powell described a means he suggested 

 for navigating the air by means of kites. He pointed out that 

 as greater height above the surface of the earth is reached, the 

 wind nearly always increases in force. .\\ looo yards it often 

 blows at three times the velocity that it does near the surface. 

 He proposes to take adx-antage of this difference by sending one 

 kite to the upper atmosphere, and keeping another nearer the 

 ground. The two kites would \k connectetl by a long line, and 

 the weight to \k carried would be attached to the line at a jwint 

 nearer to the lower kite than to the higher. The lower kite 

 would thus supply a retarding medium to the upper, so that the 

 effect would be the same in principle, though not in degree, as if 

 the upper kite were held to the earth by a string, and the lower 

 kite were towed through the air by a boy running with the 

 siring in his hand. By the forces thus brought to bear both 

 kites would be kept flying although not held to the earth by a 

 string in the usual way, and it is thought that )x)ssibly they 

 might be navigated in directions other than that in which the 

 wind might be blowing. It will be seen that the author 

 depends on the difference in velocity of currents of air at two 

 heights ; and were this difference to fail, or to become insuffi- 

 cient, the experimenter would come to the ground. This might 

 prove awkward unless a clear field were provided for the descent. 

 The suggestion however is ingenious, and no doubt many persons 

 interested in the problem of aerial navigation wiiuld be pleased 

 to see the author put his theories to the test of practice. 



The last paper presented at the meeting was a contribution by 

 Prof. A. E. Elliott, of Cardiff, on receiver and condenser drop. 

 It is a subject that deser\es far more consideration and discussion 

 by members of the Section than they were able to give on hear- 

 ing it read rapidly at the end of the meeting. Papers of this 

 nature should be read at one meeting, and tlie discussions 

 adjourned until another ; or i)erhaps it would be better to 

 distribute them two or three months before the meeting, and 

 dispense with reading altogether. A joint meeting of Sections 

 A and < 1 would afford the appropriate audience for considering 

 the subject of Prof Elliott's memoir. 



BOTANY AT THE RRITISH ASSOCIATION. 



'T'HE President (.Mr. Thisclton-Dycr) exhibited photographs 

 and specimens of a large cedar ( Ctv/rz/y Dt-odara^ Loud.) 

 from Kew, which had been struck and completely shattered by 

 lightning on August lo. It wa.s pointed out that the main stem 

 had l)ecn in [lart blown into matchwood by the violence of the 

 shiKk, and branches were lorn o.T with large portions of the 

 trunk .adhering to their base. Prof. Oliver Lodge took part in 

 the discussion as to the probable explanation of the unusual 

 nature of the explosion, which seemed lo have been centrifugal, 

 the stem having Iwen disrupted from the centre, and not merely 

 stripped superficially. 



Prof. Bretland I'armer described a set of wax models illustrat- 

 ing the typical forms pas.sed through, and the chief variations 

 exhibile«l, by the chromostmies during the division of the nucleus 

 in the spore-molhcr cells of plants. The wax employed is 

 made of a mixlure of one |)art of white wax, with fi\e parts of 

 |)arattin, the melting i>oint of which is aUiut 50° C. 



TllAI.I.OI'UVTA. 



Ex)>crimcnlal studies in the variation of yeast cellsj by Dr. 

 Emil Chr. Hansen (Copenhagen). The author gave an account 

 of his earlier and more recent investigations. Among the 

 latter he especially dwelt on those in which, by one treat- 

 ment, varieties were pr<«luced that gave more, and by another 

 trealmcnt less, alcohol than their |)arent cells. He |)ointed out 

 that the observed variations could lie grouped under certain 

 rules. From his researches on the agencies and causes to which 

 variation is due, he found that temperature was the most 

 influential external factor.' 



A false liaclrriiiiii, by Prof. Marshall Ward, F.K.S. 



f>n the formation of bacterial colonies, by Prof. Marshall 

 Ward, l-.K.S. 



(Jn the stniclurc of lactcrial cells, by Harold Wacer. In this 

 inpcr an account was given of the present state of our know- 



' A ruller accotinl of Ur. Hanscna work will lie publiihcd.in the Aimith 

 of flfitamy. 



NO. 1354, VOL. 52] 



ledge of the cells of Kicteria. Reference was made to the 

 ob.servations of Schottelius, Migula, De Bary, Biitschli, and 

 others. The author showed that it is possible to demonstrate in 

 the majority of b;ictcrial cells the presence of two sulislances, 

 one of which may be regarded as protoplasmic in nature, and a 

 second, which stains deeply when acted upon by fuchsin and 

 kindred staining substances, and which may be regarded as 

 nuclear. It was pointed out that this nuclear substance doev 

 not possess the structure of nuclei in the cells of higher plants. 



Note on the occurrence in New Zealand of two forms i>l 

 Peltoid Tniitepo/ilioific. and their relation to the lichen 

 Strigiila, by .\. \'aughan Jennings. The TiriiUpo/iliaif,,- 

 which form epiphyllous cell-plates are at jiresent known 

 only from the tropics. They have been recorded from .South 

 .-\nierica, India, Ceylon, and the East Indies, but not up 

 to the present time from New Zealand. The author 

 gave a summary of previous literature, and descrilied two forms 

 found by himself in New Zealand. ( I ) Phyiofcltis ixpaiisa, sp. 

 nov. This species forms wide-spreading yellow cell-plates on 

 the leaves of Nesodaphtw : it bears two kinds of sporangia, and 

 is often associated with brown fungus hyph.x growing between 

 the cell rows, but not affecting the growth of the alga. On the 

 other hand, when attacked by different hyph;v. the result is the 

 formation of the lichen Strigula, which in Ceylon was shown by 

 Ward to have for its algal element Myioidea parasitiia^ Cunn. 

 (2) Phycopcllis nigra, sp. nov. On leaves of Ncsodaphnc axA 

 fronds of Asptciiiuni faUatiim. Two distinct varieties of this 

 species were described. The plant is never attacked by fungus 

 hyphiv, and never takes any jjart in lichen formation, even when 

 on the same leaf with Phycopcltis cxpansa and the associated 

 Slrigula. 



BrVOI'HVTA and PlERlllOl'llVl a. 



On a supposed case of symbiosis in Tetraplodoii , by Prof 

 F. E. Weiss. The author exhibited specimens of Tetraplodoii 

 from the Cuchullin Hills in Skye, where it was found i>lentifully 

 on animal excreta. In Scpleinber he found many of the patches 

 mixed with an orange-coloured l\-iza, which did not appear lo 

 have in any way injured the moss plants. The rhizoids of the 

 moss, however, contained in many cases fungal hyphiv closely 

 resembling those of the I'cziza, and though present in the cells 

 of the moss, these latler did not seem to be injured by them. He 

 suggested that this mighl be an instance of symbiosis ; the moss, 

 as in the case of other green jilants, making use of the fungal 

 hyph^e to obtain its nutriment from the organic material. The 

 ultimate protif of such a case of symbiosis would, ln>\vever, 

 necessarily dopenil u|K)n culture experiments, which he uiuler- 

 stood were now being made by another observer. 



Remarks on the .\rchesporium, by Prof. V. O. Bower, F. R.S. 

 Prof, Bower pointed tint that the recognition of the archesixirium 

 as consistently of hypoderm.il origin cannot be upheld, and 

 (jiioted as exceptions A(////Vf7/////, IsoitcSy Opfti\\i^hssiini, and 

 especially the lepti>spoiangiale ferns. He laid down the 

 general principle that the sporangia, as regards iheir develop- 

 ment, should be studied in the light of a knowledge of the 

 a]>ical meristems of the pkants in question. Where ihe apical 

 meristems are stratified, the archesporium is hypodermal in the 

 usual sense ; where initial cells occur, the archesporium is 

 derived by periclinal divisions of superficial cells. Iniermediatc 

 types of meristein shr)w an inlerniediale type of origin of the 

 archesporium. lie cited as an illustrative case that of Op/iio- 

 glossiiiii, admitting that the hypodermal band of potential 

 archesporium, which he had previously described, does not occur 

 alw.iys or in .ill species. But so far from thus giving up the case 

 for a comparison! with I.ytopodium, he hoMs tliatas Ophioglossum 

 h.as a single initial cell in stem and root, it would be contrary to 

 exiierience to exjiect or demand a hypodermal arcliesjioriuni. 

 (The details will shortly be published elsewhere, with illustrations.) 



On the prothalUis and embryo of Daiiica, by G. Brebner. 

 .Mr. Brebner gave an account of the jirolhallus and sexual 1 

 organs of Daiuta siiiiplidfolia, Kudge, a,s the result of investi- 

 gations mailc on some material from the Botanic (hardens 

 in British (iuiana. He pointed out that there is a close 

 similarily belween the Paiina anil the other twn genera cif (he 

 Maratliai(,r, .liigiopliris and A/aratlia, of which llie prothallus 

 has Iwen previously described. .Vn interesting fact was noted 

 as regards the prothallus rhizoids, which possess a distinctly 

 .septate structure, and so far resemble a moss proloneina. 

 Possibly similar septate rhizoids may be found in the oiher 

 maralli.iceons genera. The development of the antheridia of 

 Daiiica agrees in the main with that in Afaraltia AniX Angiopleris : 



